I've ridden a lot in the backcountry. I've ridden a lot of single track deep in the woods, with aspens and conifers and whole lots of cover edge the side of trails. And one of my biggest fears when flying through these areas isn't hitting a rock or clipping a tree branch. No, it's encountering wildlife.
Now, for the most part, I don't mean wildlife that feature sharp teeth and razor-like claws. Those animals tend to, I SAID TEND TO, leave most riders alone, whether they're on dirt bikes, snowmobiles, or ATVs. Bears and lions, unlike elk and deer, don't like the sound they make. But the deer and elk have become so accustomed to these noises that they really don't care about them, which makes encountering them along the trail all the more dangerous.
Yet, it's when they get close to the trail and then get spooked by said machines where conflict arises. And you can see all of that in action captured recently by two dirt bike riders who were just minding their own business until a deer comes flying in screaming "HIS NAME IS JOHN CENA!"